Edelbrock heads on 428, can I make 500 hp?

[jared1970]

I'm ordering some Edelbrock RPM heads for my 428. I really want to make around 500 hp. Is that possible with these heads as-cast? I'll be running a Performer RPM intake. This is going to be a street driven motor, so the cam duration @ .050 is going to be kept below 250. This is my first experience with an FE, and with Edelbrock heads. So, any of you FE experts with experience with the Edelbrock heads, I'd like your input. Will I need the heads ported? If so, how extensively? Thanks.

[SCOBRAC]

Yes.

10.5:1 with a 250 degree solid lifter .600", roller rockers. Make sure the intake matches but you shouldn't need to port the heads. 750-850 double pumper you should have legit 500 hp.

[decooney]

For the small additional cost, I still feel its is well worth having your heads/intake port matched, with at least some mild porting. ...and as you are probably aware, there's nothing like the crackle of a breathing FE through sidepipes on a Cobra or through big chamber exhaust on a musclecar.

[joea]

IMHO pulling 500hp out of a 428 isn't as easy as everyone makes it sound.

[Joe Prochazka]

I went through this a couple of years ago. The key to making the HP numbers that you want will be your cam and heads.
My engine builder said that the Edelbrock RPM out of the box were little better than stock replacement heads. I was skeptical until I took them to Bob Mckray Performance-one of the best head shops around here. He agreed.
To bump up compression you will have to deck the heads. Edelbrock Technical Service gave me the numbers of .006 of material to reduce chamber volumn by 1 cc. Out of the box the heads were 72 cc, we figured that 68cc was what we need to get 10.25 compression. So that meant about .024 should come off. Don't do it all at once. Your engine builder or yourself need to check piston to valve clearance along the way. I think that we took .020 off, checked clearane and the ended up taking another .010 to get to 10.25.....the
edelbrock numbers were a little off.

Another thing, the RPM springs are a POS and will not support .600 lift. At least not for long. We had to upgrade valve spring and you will have to add spring cups. the stock RPM's springs seat on an aluminum boss, best to add a steel cup for your spring to seat into.

The intake runners are only 170cc on the rpm's so there is room to clean up the intake runner with mild porting and intake matching is a must. I think the exhaust ports on my engine were just smoothed out a little.

Don't for get to have the head shop install oil restricters on each head. I went to .090 on these.

You will need a good roller rocker with end stands. I used the Dove/Comp Cams. Pricey. I hear that the Ersons are the way to go now but they were not available when I as going through my build.

You might want to consider shell lifters for your solid cam. They are solid lifters that have been hollowed out in a taper pattern. Removes weight. You will need custom push rods anyway so use the light lifters. They will require a longer pushrod. I had 3/8 ones made up

I used a Crane custom grind solid cam. 238/248 duration @ 50. 110 lc. This combination has worked out well and shakes the whole damn house when I light it off.

Hope this helps.

[Sizzler]

I got 10.6 CR without decking jack.
Needed to order custom pistons anyway, so got flat-tops and sized to basically be even with the deck.

Still have not found a legitimate reason for restricting oil to the heads, at least not for street purposes, other than "that's what everyone says to do". Millions of FE's were built and lasted for billions of cummulative miles without restricting the oil, or boring out the oil passages. The thing you do need to watch out for it making sure the oil drainback passages are clear, and remain clear with all gaskets in place. Also, it's a pain, but try to get the oil 'fingers' installed, they help drainback too. You may need to experiment with different styles.

And I agree that getting 500 HP out of 428 cubic inches isn't as easy as some people think. A lot of people cheat and bore/stroke the engine out to high-400's or even more, call it a 427 and say its got 500 HP. Whoopteedo. Why the 500 number?
Especially with a 428? You'll want to spin things up pretty high to get that number (hence the recommendation vis a vis cams and lightweight valvetrain components).

[Joe Prochazka]

Sizzler,
Yes, there is more than one way to boost compression...all it takes is money.

As far as modifying oil passages, when I was planning my engine I talked to 2 guys who participate on this forum who have over 30 years of FE building experience each. If they say do, then I'm going to do it. If you choose not to......well whatever floats your boat.

[decooney]

On my motor, we found that with all the required oil passage and drainback blueprinting completed, we still had to slightly restrict oil to the heads when using a high volume/pressure oil pump that I chose. Otherwise, oil still pooled too much. Ran it on a motor stand for a bit til we got the correct amout of restriction. I would venture to say it might be a little different with each motor dending on who does the work and how its set up. Good Luck.

[joea]

How did you determine the correct amout of restriction?

[decooney]

Joe,
...just enough to keep pooling under the valvecover gasket level during sustained operations. An eyeball of an obvious flow or balance of incoming to exiting oil; not overrunning or underunning flow. This was tested under a range of sustained RPM checks, on the stand. Seems to be okay with well sealed valvecover gaskets.

[bomelia]

This all very interesting. I am finally to the point where I need to start researching heads. I have planned all along to go with Edelbrock RPM heads. I have a 428 SCJ block, bored 30 over.

The cam selection is for 400 hp. But, I admit to knowing very little here. Any ideas on head selection?

Mike

[joea]

Choices are limited for the 428 due to the smaller valve size. I recommend the Edelbrock Performer FE heads...I bought mine pocket ported from Flatlander Racing.

If you have the extra money and want to fully port them, I would probably go with the Keith Craft CNC port. I may do this in the future.

Actually on second thought I hear Blue Thunder has heads out or comming out soon. If they had 428 heads I would seriously consider them. I hear they will flow better out of box than the Edelbrocks and their quality is awesome

[Keithc8]

We buy our Edelbrock heads bare so that we can install the parts that we feel are best suited for the application. The springs, retainers and locks that come on the Edelbrock heads leave a little to be desired. You can also install larger valves if you want to this way. Depending on the bore size you can run a 2.150 intake and a 1.72 exhaust valve. We also do a special valve job and back cut on the valves that picks these heads up about 20 to 25 cfm on the intake at .500 and .600 lift with out hurting the low flow. We sell a assembled pair of heads with all of our parts and valve job work for 1495.00. These include 10 degree retrainers and locks, dual springs, spring cups and seals. We supply a parts list, assemble heights and spring pressure set p for your application. You can also go the CNC stage 2 heads for only 2195.00 and these will support 600HP. Good luck, Keith Craft

[hoppy]

Hi Keith,
My 428 SCJ has original heads, high riser manifold, 10.7:1 compression (according to the original owner and assembler of the engine), Comp Cams solid lifter cam (I think 280 is grind number if I remember correctly) and roller rockers.
If I were to switch to either of the Edelbrock head set ups that you have described, what level of benefit in both HP and torque would you estimate I would derive from each and:
1. Would you need my intake to match the ports (is this necessary or reccommended)
2. Does this become a straight bolt on modification that most "home mechanics" can accomplish?
3. Would I need to change or add any additonal components to complete or even enhance the installation.
4. Would this modification significantly change the "power band" from it's current range?

I am reluctant to pull then engine and/or make any "bottom end" rebuilds as my ERA and engine only have about 4,000 miles on them are are running great at this time. It's just the lure of a possible big gain in performance without major motor work that is tickling my fuel damaged brain cells.
Thanks
Terry

[Keithc8]

Hoppy,
I have a couple of questions for you. You say a high rise intake, are we referring to the original 428CJ intake? If you are running 10.7 to 1 compression now with cast iron heads are you having any problems with detination or do you run better fuel.
If your heads have mild work done to them the Edelbrock stage 2 heads should pick you up between 40 to 50HP. You may have to do some tuning to the carburetor to maximize gains. I would also recommend running the rocker studs in the heads for the valvetrain. I was also wondering if you have the stock rocker system or aftermarket?
I feel that someone with above average mechanical skill could change the heads out with no real problems. I could answer any questions you might have when you did it. I would recheck rocker geometry when install new heads but should be very close. I would also like to know what piston is in your engine because of piston to valve issues. Sometimes we install a little larger valve than stock if piston will take it. Hope this helps a little. Thanks Keith Craft

[hoppy]

Hi Keith,
Thanks for taking the time to reply. From what I read here you are an awfully busy guy.
I need to do some additional homework to answer your questions but what I have at hand from receipts ect. supplied by the orginal owner/builder I will tell you this much:
Cam: Comp Cams grind number FB 282S-10, Gross valve lift - 0.571 intake and exhaust
Duration at 0.015 tappet lift - 282 intake and exhaust
Valve timeing at 0.015: Intake Open 35, Close 67, Exhaust Open 75, Close 27
Duration at 0.05 - 236 intake and exhaust
Lobe lift - 0.33 intake and exhaust
Lobe separation - 110
Receipts from Cobra Restorers for Part No. CP1012 Plenum Chamber
Receipts from Summit for:
CCA-1046HD-Kit Rocker arms and Valve springs 1.265 DIA 115 lbs ! 1.700 350 lbs @! 1.15
Receipts fvrom Tony Branda for:
AIM 5 BB 1X4 High Rise Intake

Machine shop work including Balancing Crank Assbly, grinding flywheel, recondition rods, bore and hone cylinders, grind crank 0.010 under, mill block decks, align hone block main bores, install main stud kit, machine main caps to clear studs, rebush rods and bore center to center length, Drill pistons for pin oiling, pin fit pistons. I think the block is bored "40 over
Heads were machined and SS valves installed
I don't know what pistons were used but no problems with the compression producing detonation on 92 octane gas.

I have overseas business visitors for about a week so I don't know if I can dig up much more till that's over but I wll.

I was kinda hoping to find up to 100 HP without yanking the engine and pulling out the slugs, etc. Maybe I am being to optomistic.
Anyway appreciate your input and hopefully we will get together on some improvements for the motor at some point.
Thanks,

Terry

[Keithc8]

hoppy I think you can get close to the much with out removing the pistons if we can install a little larger camshaft with out fly cutting pistons. You could go to a hydraulic roller which fills the cylinders better even with the same duration. If you have the stock type rocker arm system you could go to a Erson roller rocker system. What I would recommend would be a set of our Stage 2 Edelbrock CNC heads with one of our custom hydraulic roller camshaft with the Crane lifters and Smith Brothers pushrods, indexable timing set where we can install the camshaft 4 degrees advanced. We can also rework the craburetor or replace it and achieve some HP as well. The heads, camshaft, lifters, pushrods, Erson roller rockers would set you bacl about 3700.00 including the head gaskets and intake gaskets. Hope this helps you with your decision on what you want to do. We have made these same changes on a few engines and picked up about 70 to 80 HP at the rear wheels. Thanks Keith

[jared1970]

Hey, Keith, I'd like to contact you to talk about your heads. Is there a phone number I can call you at? I'm not sure if your Stage 2 heads are what I need. I'd like to discuss in detail with you what my plans are and see what your opinion is.

[hoppy]

Keith, thanks for the input. I'm not ready to make the changes yet, but it sounds like the most practical way to punch it up enough for some additional slam in the back. I will certainly keep it in mind when I find out where my wife buried the coffee cans full of cash she claims were spent on groceries.

[Keithc8]

jared 1970 you can call me at 870-246-7460 Monday through Friday between 9:00 and 6:00. I will try to help anyway I can. Thanks Keith